Come on, Google is your friend. I searched for "symbolic differentiation" & found several hits to projects & code libraries which do exactly what you are wanting to do. Granted, a number of these are written in languages other than Ruby, but you should still be able to understand them well enough to get an idea of where to start on your own.
Jim
-------------- Original message ----------------------
From: SleepJunk13 <SleepJunk13 / GMail.com>
> So.. I have no idea where to start.
>
> I'm starting to think even this is too big for me to do. I've only made
> small programs before. I'd really like a place to start, or something to
> help get me started. I'm going to have to be able to parse so many
> different things.
>
> Maybe I need to learn more Ruby. I'd love to do this, though.
>
> --
> Posted via http://www.ruby-forum.com/.
>